Electrically heated vapor spray generator



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ELECTRICALLY HEATED VAPOR SPRAY GENERATOR Filed Dec. l2, 1958 5 Sheets-Sheet 1 mm M. SIMMONS} J2.

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THE/z A 1' 7'0 RA/EY ELECTRICALLY HEATED VAPOR SPRAY GENERATOR Scott A. Norris, Jr., Ross Township, Allegheny County, and Donald M. Simmons, Jr., Osborne, Pa., assignors to Homestead Valve Manufacturing Company, Coraopolis, Pin, a corporation of Pennsylvania Filed Dec. 12, 1958, Ser. No. 779,901

7 Claims. (Cl. 239-437) This invention relates generally to vapor spray generators in which the liquid and heat are supplied to a heating zone at a rate correlated with each other to produce from the liquid a vapor spray within a latent heat Zone and more particularly to a vapor spray wherein a constant electrical heat is supplied and the liquid supplied is correlated therewith to proceed the vapor spray within the latent heat zone.

The use of an electric heater in a heating zone to heat spray liquid and produce a vapor spray within the latent heat zone presents the problem of maintaining the generation within the latent heat zone without control of the voltage or current supplying the heat.

To accomplish vapor spray generation under these conditions the supply of liquid is correlated with the supply of heat so that the generation will be within the latent heat zone under normal fluctuations of voltage that changes the supply of heat and motor voltage without unbalancing the correlation so that the spray generated will be out of the latent heat zone. This limits the control to conditions where the heater is merely shut ofl to avoid improper generation that might tend to destroy the equipment. Such conditions occur when there is a failure of the supply of water to the machine which is stopped upon the stoppage of the flow of water and not until the tanks are depleted. Again if the voltage drops low enough to drop out the contactor the heaters will be cut out and requir a manual reset to revive the heat.

Another controlled condition of this invention is when the pressure generated is too high, the heat is interrupted until the pressure is lowered.

Another object is the provision of a temperature control which would interrupt the supply of electricity to the heater when the temperature of the heating coils exceeds a predetermined temperature whether or not a fluid mixture is in the heating coils. Thus if the water supply is interrupted, the pump fails or a hose or line breaks allowing the liquid or fluid to escape, then this control functions to interrupt the electrical circuit until the normal temperature has been restored.

Another object is the provision of an electrically heated vapor spray operating within the latent heat zone wherein the volume of the liquid supplied may be correlated with heat supplied at a predetermined voltage. Such a machine may have a mere manual switch means to turn the heater and pump on or off with pump circuit first closing. Such a manual switch means may bereplaced by a manually reset contactor wherein any liquid float or flow control, pressure and temperature switches would function to release the contactor upon predetermined conditions. A further step in the same control of a liquid float, or flow control pressure and temperature switches may be connected with an automatic reset contactor wherein the controls function to modulate the operation of the spray generator under proper liquid flow, pressure and temperature conditions.

nit-e States Patent i Other objects and advantages appear hereinafter in the following description and claims.

The accompanying drawings show for the purpose of exemplification without limiting this invention or the claims thereto, certain practical embodiments illustrating the principles of this invention wherein:

Fig. 1 is a schematic view of the electrically operated vapor spray generator comprising this invention.

Fig. 2 is a schematic view of the electrically operated vapor spray generator comprising this invention and provided with a pressure control switch.

Fig. 3 is a plan view of the electric coil heater shown in Figs. 1 and 2.

Fig. 4 is a side elevation of the coil heater shown in Fig. 3.

Referring to Fig. 1 of the drawings, the vapor spray generator is supplied with liquid from the water supply tap 1 which is connected by the flexible hose 2 with the vapor spray generator inlet line 3, to which is attached the flow switch 4. The flow switch 4 functions to maintain a closed electrical circuit through the lines 5 and 6 when a liquid is continuously supplied through the inlet pipe 3 to the water float tank 7. If the liquid ceases to be supplied through the inlet line 3 the flow switch 4 will automatically open the circuit between the lines 5 and 6, thereby interrupting the current flow therethrough. The water flows upwardly through the supply line 3 to the float valve member 8 from whence it is discharged downwardly into the water float tank 7 and the amount of water supplied thereto is determined by the float member 10 which controls the supply of water through the valve 8 by reason of the movement of the float 10 on the surface of the water in the tank 7.

The liquid level in the tank 7 operates switch 9 which is connected in Series with the contacts of the flow switch 4 or one may elect to have either the flow switch 4 or the float switch 9. Thus when the generator is operating continuously the float valve may control the flow of water to the tank 7. Thus under normal operation the fioat valve continuously admits water to the water float tank 7.

A solution tank 11 shown at the opposite end of the generator is provided with a mixture of water and solution through an opening in the top thereof which is not shown and this solution is pumped through the line 12 to v 14 and the outlet valve 15 the discharge of the pump 13 is supplied to the line 16 which returns the solution to the tank 11 through the restrictor check 17. That portion of the solution that does not return to the tank 11 flows through the solution line 18 to the solution metering valve 26 on the panel 21. Thence it flows through the line 22 to the water float tank which then becomes a solution tank having the proper mixture of solution with the Water for use in the vapor spray generator. Dilferent degrees of solution concentration of course may be controlled by the solution metering valv 2%) and the solution tank 11 contains the concentrate and maintains a proper balance in the solution concentration until the tank is depleted.

The line 23 from the water float tank 7 supplies the water and solution mixed therewith to the water pump 24 which is provided with the inlet valve 25 and the outlet valve 26. All of the solution passing from the pump 24 travels through the line 27 through the heating zone 28, which in this instance comprises the electrically heated coil 30 which receives the water and solution from the inlet 31 and which travels through the first section of the heating zone in the form of the coil 32 and thence through the cross connection 33 to the second section of the heating zone in the form of the coil 34, and thence through the cross connection 35 to the third section of the heating zone in the form of the coil 36, after which it is dischargedthrough the line 37 to the vapor hose discharge 38 and the vapor cleaning gun 40 to atmosphere. Top or last coil 36 has mounted thereon the thermostat 39 which is preferably a temperature responsive means with an adjustment to have its contacts open at diflerent selected temperatures. The normally closed contacts of this thermostat 39 are connected in series with the normally closed contacts of the flow switch 4 and the float switch 9.

The pressure line 41 connected to the line 37 supplies the heated vapor spray solution to the gauge 42 on the panel 21 for the purpose of informing the operator the pressure generated by the vapor spray generator.

Between the line 37 and the hose 38 a fuse plug 43 is provided which if for some reason the vapor spray generator becomes out of control will melt the fuse plug 44 and the generator vapor will discharge directly through a hole in the plug 44 and thus bypass the hole and prevent it from being burned by being overheated.

The pumps 13 and 24 are operated by opposite ends of the piston 45 which is connected by the yoke member 46 and the connecting rod 47 to the crank 48 on the wheel 50 operated by the V-belt 51 on the electric motor 52. This V-belt pulley drive may be adjustable to vary the volume of the liquid supplied to the heating coils in conformity with the voltage or heat supplied. This variable volume control is particularly advantageous when the system is employed without any controls whatsoever and a mere manual switch is used to turn the machine on or off.

A combination drain and relief valve 53 is provided at the inlet 31 of the heating zone.

The heating zone 28 in the form of the three coils 32, 34 and 36 which are all connected in series by the cross connections 33 and 35 depict a sheathed electric heating element passing coaxially through each coil section. These three electric heating elements 54, 55 and 56 are shown connected in delta with junctions 57, 58 and 59 connected by lines of the same number to the switch contacts 60, 61 and 62 of the switch 63. The switch 63 may be in the form of a simple manually operated switch or it may be a contactor provided with an energizing coil as shown. The supply circuit, of course, could be any phase or hookup, however three phase provides a better balanced circuit than single phase. The opposite side of the contacts 60, 61 and 62 is connected to a three phase supply line L1, L2 and L3 respectively to the drop cord cable indicated at 64. The contactor 63 is provided with an energizing coil 65, one side of which is connected by the line 66 through the fuse 67 to the line L2, the line 66 being also connected to one side of the switch blade 68, the other side being connected to the line 69 to one side of the motor, the other side of the motor being connected 'to the line 69 to one side of the motor, the other side of the motor being connected by the line 70 to the switch blade 71 to the line 72 which is connected through the fuse 73 to line L1. Thus when the motor switch 74 with its blades 68 and 71 close the supply of current directly from the lines L1 and L2 to the motor to operate the pump the motor of which is protected by the fuses 67 and 73 as well as the ordinary motor overload protection usually found on such motors.

The motor line 70 is also connected through the connector 75 to the line '5, the three controls 4, 9 and 39 to the line '6 which is connected through the connectors 76 to the line 77 which is connected to one side of the single pushbutton 78, the other side of which may be connected to the line 79 that extends to the opposite side of the coil 65. Thus the pushbutton 78 will not receive energy until the motor circuit is energized. The line 79 is also connected to one side of the contactor switch 80, the other side of which is "connected to the line 77. This traced as follows.

places the contactor 80 in multiple with the pushbutton 79 so as to provide a stick holding circuit. Once the circuit through the energizing coil 65 is made by the pushbutton 78 then the same closes each of the contacts 60, 61, 62 and 80. The stick contact 80 maintains the coil 65 energized even though the pushbutton 78 is released and the only time that the contact will be deenergized is in the case of a power failure, the blowing of one of the fuses 67 and 73, or the opening of the double pole knife switch 74, or the interruption of the flow of water to the flow switch 4 or the float switch 9 or the thermostat 39. I

A heater light indicator 81 is connected across the line 77 and the line 82. Thus the heater lightindicator is supplied with current from lines L1 and L3 but on the load side of the contact switch 62. Thus when the switch 74 is closed and the pushbutton 78 is depressed to pick up the contactor 63 the electrically operated vapor spray generator will continue to function until there is a power failure or a water supply failure or water level failure or if one of the fuses burn out or if the temperature of the coil rises beyond a predetermined amount.

The structure shown in Fig. 2 is similar to the structu-re illustrated in Fig. 1 with the exception that the contactor energizing coil 65 is not provided with a stick circuit and the pushbutton switch 78 is replaced by a switch member 78a. The pressure line 41 is also provided with an extension that is connected to the pressure control switch 83. This pressure control switch is arranged to operate the contactor 84 placed in series with the lines 77 and 6. Thus if the pressure generated by the vapor spray is excessive or if the temperature is too high or the flow switch 4 or the float switch 9 open anyone will open the contact 84 between the lines 6 and 77 and thereby interrupt the current flowing through the energizing coil 65 of the contactor 63. This circuit may be The current from L1 travels through the fuse 73 to the line 72 and thence to the switch blade 71 of the motor switch 74 to the line 70 and thence from the line 70 to the connector 75, thence from the connector 75 to the line 5 of the flow switch 4, the float switch 9, the temperature switch 39, and back line 6 to the contact 84 of the pressure control switch 83 to the line 77, thence to the 1ines77 to the switch 78a to the line 79 to one side of the coil 65 and from the side of the coil 65 to the line .66, the fuse 67 to the line 2.

The heater light indicator 81 is connected on one side of the line 70 which is connected by the switch blade 71 to the line 72 and thence to the fuse 73 to the line 1 and on the other side by the line 82 to the load side of the contactor 62 as indicated by the line 59. Thus the line 70 that is connected to the switch blade 71 determines the energization of the coil 65 as well as the motor 52. Again the flow switch 4, the float switch 9, the temperature switch 39, the pressure temperature control switch 84 and the fuses are all placed in series with the operating coil 65 so that the spray generator will-be interrupted by the lack of flow or level of water, an excessive temperature, or pressure by the control switch 84.

Referring to Figs. 3 and 4 the coils 32, 34 and 36 are shown to be three sections of helical coils made of pipe with their ends extending tangentially from the helix on the same side. Each of the coils 32, 34 and 36 is the same and is provided with a reducing T at each endv thereof, the reduced portion 91 being secured to the metal sheath 92 of the electrical heating element 93 having opposed terminals 94 and 95 at the opposite ends thereof which are insulated as indicated at 96 from the metal sheath 92.

The sheath in this instance is preferably copper and is silver soldered as indicated at 97 through the reduced T section 91 so that the fluid outlet of the coil is the lateral or stem section 98 which are connected to adjacent coils by the connections 33 and 35 respectively.

As shown the heater elements 93 extend substantially coaxially through each coil section and permit the liquid to flow thcrearound. Each coil section is supported by the standards 100 and 101 which have brackets 102 bolted thereto for supporting the coils in tandem to each other. The inlet is indicated at 31 in the bottom of Fig. 4 and the outlet is indicated at the top line 37 with the liquid flowing through each coil in turn and with the electric terminals being connected as illustrated in Figs. 1 and 2 in a delta connection or a three phase circuit.

Obviously the liquid is not heated when it transfers from one coil to another through the connections 33 and 35. However the flow is continuous and this short interruption is ineffective and can be readily compensated for. It will also be noted that the liquid is provided with ample room around the coil heater as it follows through the pipe and surrounds the heater.

We claim:

1. An electrically heated vapor spray generator comprising a cleaning gun, a heating coil connected to supply said heating gun with a cleaning fluid, a liquid supply reservoir having a feed line to continuously supply liquid thereto, a flow switch in said feed line, a solution tank, a pump to feed solution from said solution tank to said liquid'supply reservoir, a second pump to supply liquid solution from said reservoir to said heating coil, a motor for continuously operating said pumps, an electric heater element carried by said heating coil to supply constant heat to the liquid in said coil, an electromagnetic switch having contacts to connect said heating element to an electric supply, an operating coil for said electromagnetic switch, a control switch connected in series with said operating coil and said flow switch to form a circuit, a second control switch and circuit for supplying current to said motor and to said series circuit, and a front contact on said electromagnetic switch connected in multiple with said first control switch, said motor operating said pumps to supply liquid to said pipe coil :at a predetermined rate correlated with the constant rate of heat supplied thereto to produce a vapor and a liquid of said vapor under pressure to generate a spray.

2. The structure of claim 1 characterized in that said first control switch is a thermally operating switch.

3. An electrically heated vapor spray generator consisting of a pipe coil with an inlet connected to a liquid float tank having a continuous source of liquid, a spray gun connected to the outlet of said pipe coil, a solution tank, an electric heater means carried by said pipe coil for supplying a constant heat to the liquid therein, an electric motor operated pump for continuously supplying solution to said liquid float tank and supplying liquid from said liquid float tank to said pipe coil at a predetermined rate correlated with the constant rate of heat supplied thereto to produce a vapor and the liquid of said vapor under pressure to generate a spray within the latent heat zone and issuing from said gun.

4. The structure of claim 3 characterized by a switch to continuously supply current to said motor, a contractor having contacts to supply current to said electric heater means and having an operating coil, a flow switch actuated by the continuous supply of liquid to said liquid float tank for said vapor spray generator, a heater start switch, and a circuit connected from the motor side of said motor switch through said flow switch to said heater start switch and from the other side of said heater start switch to the operating coil of said contactor.

5. The structure of claim 4 characterized by an indicator light connected to be energized when said heater is energized.

6. The structure of claim 3 characterized by a switch to continuously supply current to said motor, a contactor having contacts to supply current to said electric heater means and having an operating coil, a flow switch actuated by the continuous supply of liquid to said liquid float tank for said vapor spray generator, a heater switch, a pressure switch actuated by the pressure of the generated spray, and -a circuit connected from the motor side of said motor switch through said flow switch, said pressure switch, said heater switch and the operating coil of said contactor.

7. An electrically heated vapor spray generator comprising a liquid heater in the form of a pipe with an inlet connected to a source of liquid and an outlet connected to a spray gun, an electric heater means connected to said pipe for supplying a constant heat to the liquid therein, an electric motor operated pump for continuously supplying the liquid to said pipe at a predetermined rate correlated With the rate of heat supplied thereto by said electric heater to produce a vapor and the liquid of said vapor under pressure to generate a spray issuing from said gun, and heater control means between said spray gun and said heater to turn said electric heater on and ofi to maintain said generator in the latent heat zone while the liquid is continuously passed through said generator.

References Cited in the file of this patent UNITED STATES PATENTS 965,333 Robinson July 26, 1910 1,905,439 Carleton Apr. 25, 1933 2,041,071 Keegan et al. May 19, 1936 2,117,419 Hamrick et al. May 17, 1938 2,623,153 McGinnis Dec. 23, 1952 2,627,015 Hackman Jan. 27, 1953 2,720,868 Wollner et al. Oct. 18, 1955 2,790,678 Arant Apr. 30, 1957 2,851,053 Wollner et al. Sept. 9, 1958 2,861,838 Wyatt et al Nov. 25, 1958 2,919,070 Arant Dec. 29, 1959 FOREIGN PATENTS 994,870 France Aug. 14, -1 

